Electric switch



July 18, 1933. s. RUMP 1,918,869

ELECTRIC SWITCH Filed Dec. 6, 1930 V9 for lggrd Rump Patented July 18, 1933 SIGURD BUMP, OF ZURICH,

SWITZERLAND,

ASSIG-NOR TO AKTIENGESELLSCHAFT BROWN, BOVERI 8c (3113., OF BADEN, SWITZERLAND, A JOINT-STOCK COMPANY OF SWITZERLAND ELECTRIC SWITCH This invention relates to improvements in switches for the interruption of electric circuits and particularly to switches which are in effect subdivided into a fuse or safety element to disconnect currents in the nature of short-circuits and a main switch element which disconnects the normal operating current.

In switches of the character above referred to, theswitch element must interrupt the short-circuit current at a voltage corresponding to the voltage drop over the fuse element.

If the fuse element has an appreciable resistance, the voltage to be disconnected thereby becomes excessively large so that the resistance of the fuse element mustbe reduced as much as possible. Such reduction is impossible if water or a solution of a salt with a high specific resistance is used in the fuse element. The replacement of the usual fuse wire by water is however very advantageous because of the general availability of water and the fact that it does not form dangerous vapors. Mercury has a much smaller specific resistance but is expensive and the vapors formed t iere from are poisonous and hence must be confined in a closed container. Use of such closed container is however dangerous due to the possibility of explosion therein.

It is, therefore, among the objects of the present invention to provide a combined electric'switch and fuse element in which fluids replace the usual fuse wire. 35 Another object of the invention is to provide a combined switch and fuse element in which both mercury and water are used as the current interrupting means.

Another object of the invention is to provide a combined switch and fuse element in which mercury and water are both used within a closed container without incurring the danger of explosion of the fuse element.

Another object of the invention is to pro- I vide a combined switch and fuse element of the character above mentioned in which the fuse element is formed as a plurality of parallel connected portions.

Objects and advantages, other than those above set forth, will be apparent from the 500,491, and in Germany Becember 9, 1929.

following description when read in connection with the accompanying drawing in which Figure 1 is an embodiment of the invention showing a fuse element thereof in sec- 2 is a fragmentary portion showing simplified embodiment of that shown in 1 likewise shown in section,

fig 3 is a further modification of the invention showing a still further simplified embodiment of tie invention illustrated in Fig. 1, and

Fig. 4 is a modification of the invention A which the action by which the electric ircuit is interrupted is slightly different rom that taking place in the embodiments shown heretofore.

Referring more particularly to the drawing by characters of reference, the main switch element which is required to carry and interrupt the normal operating current comarises a pair of cont-act members 6, 6 which are connected with the circuit 7 7 to be interrupted and which are bridged by a member 8 preferably in the form of a laminated brush pivotally mounted on a fixed support 9 as shown.

The fuse element is formed as a pair of end members 11 and 12 on which the contacts 6 are" mounted and which are connected by a plurality of tubes 16 and 17 formed of insulating material and a tube of which the portion 18 is made of insulating material while the portion 18 connecting the portion 18 and tube 16 may be made of conductive material if desired. The end member 12 is made as a closed container provided with an apertured partition 19 and having an car 21 extending therefrom which is pivotally mounted on a support 22 to permit clockwise rotation of the fuse e einents by any known suitable operati. means. The pivoting point of the fuse element is preferably so located with respect to the center of gravity of the structure as to accelerate the movement of the element as will be described. The end member 12 and the tubes 16 and 17 respectively are filled with mercury and water or a salt solution to the level shown in the drawing. The tube 18 18 is filled, above the level of the mercury shown therein, with a gas for a purpose which will be set forth hereinafter.

During a normal flow of current over contacts 6 and brush 8 from the line 7 only a very small quantity of current flows through the mercury and water between the end member. hen the circuit is to be interrupted, the fuse element is tilted in a clockwise direction to cause separation of contacts 6 and brush 8. Due to the lower resistance of mercury, the greaterportion of the current flows through the me fcury which is vaporized and flows into the chambers formed in the end member 12. The current then flows through the water which is heated so rapidly that the water is vaporized and ejected from the tube into the chambers in the end member whereupon the current is interrupted. The current which must be disconnected by the switch element is thus kept at a very low value and damage to the contacts is avoided. The switch is. of course, re-connected upon return of the fuse element, in a counterclockwise direction to its. original position. The partition 19 prevents the return of the greater portion of the water to the tubes until after return of the mercury and the water remainina in tube 16 is displaced by the mercury. Tube 18, 18 permits displacement from and return of the air or other gases to the end member responsive to the movement of the mercury and the water. A pressure equilibrium throughout the entire structure is thus obtained a d all danger of the occurrence of local. stresses therein avoided.

It is not necessary that tubes 16 and 17 be arranged in a parallel relation to each other but the tubes may be arranged within each other as shown in Fig. 2 if only one fluid is used in the fuse elements. Tube 17' may thus be shortened and the entire structure becomes very much more compact.

A. single tube may also be used as shown in Fig. 3 in which the tube 16 is closed at the one end member 11 and the tube is of such size as to permit the use of two different fluids. The action in the present modification shown dilfers from that above described and applicable to the structures shown in Figs. 1 and 2, in that when the fuse element is tilted, the water is forced into the end of the tube adjacent end member 11 so that the mercury and water are in series in the circuit. The water is at least partially vaporized and the circuit is broken.

Fig. 4 illustrates a modification of the invention in which the end members differ from the construction of the end members previously shown in that the member 24 is also hollow thereby affording connect-ion between tubes 16 and 17 and end member 25 is without a partition. When the fuse element is tilted, in a clockwise direction, to separate the contacts from the brush, the

mercury partially flows into end 25 until the level of the mercury is within the tube, a portion of the water flows into end 25 and the remainder thereof rests upon the mercury 1n tube 16 so that both the mercury and the water are in series in the circuit. The heating effects of the current vaporizes the water which interrupts the circuit. The tube 17' permits pressure equalization between the several portions of the structure which avoids the necessity for the tube 18.

It is to be understood that the fuse element should be rotated slightly farther than is absolutely necessary to secure mere interruption of the circuit for the pur ose of avoiding an undesirable flashover along the tube. hen. different fluids are used, it is necessary that they be immiscible and it is desirable that the fluids be so chosen as to have suitable relative resistances.

Although but a few embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

The invention claimed is:

1. In an interrupter for electric circuits, a pair of electrodes comprising terminals for an electric circuit, a switch element disposed for connection with and disconnection from said electrodes to establish a conductive path t-herebetween, and a plurality of electrically conductive fluids operative to establish parallel paths for the flow of current between said electrodes upon connection thereof with said switch element, and operative to interrupt conductive connection therethrough between said electrodes upon disconnection of said electrodes from connection with said switch element.

2. In an interrupter for electric circuits, :1 pair of spaced electrodes comprising terminals for an electric circuit, a switch element disposed for connection with and disconnection from said electrodes to establish a path for the flow of electric current therebetween, and a plurality of vaporizable electrically conductive fluids operative to establish parallel paths for the flow of electric current between the said electrodes in shunt connection with the said path by way of said switch element, the said fluids being vaporized upon interruption of connection of said electrodes with the switch element to'thereby prevent flow of electric current between the said electrodes.

3. In a interrupter for electric circuits, :1 pair of spaced electrodes comprising terminals for an electric circuit, a switch element disposed for connection with and disconnection from said electrodes to establish and interrupt an electrically conductive path between said electrodes, a plurality of tubes of insulating material extending between said electrodes, vaporizable electrically conductive fluids contained within said tubes comprising parallel paths for the flow of electric current between said electrodes in shunt connection with the said path by way of said switch element, the said fluids being vaporized responsive to flow of electric current therethrough upon disconnection of said electrodes from connection with said switch element to thereby prevent flow of electric current between the said electrodes.

4. In an interrupter for electric circuits, a switch element, a pair of spaced electrodes comprising terminals for an electric circuit movable into connection with and disconnection from said switch element to establish a path for the flow of electric current between said electrodes and to interrupt the flow of electric current between the said el ctrodes, a plurality of tubes of insulating material extending between said electrodes, vaporizable electrically conductive fluids of different electrical characteristics contained within said tubes comprising parallel paths for the flow of electric current between said electrodes in shunt connection with said path by way of said switch element, the said fluids being irnmiscible and being vaporized responsive to flow of current therethrough upon interruption of connection of the said electrodes with said switch element to thereby prevent flow of current between said electrodes.

5. In an interrupter for electric circuits, a switch element, a pair of spaced electrodes comprising terminals for an electric circuit, the said electrodes being movable in one direction to connection with said switch element to thereby establish path for the flow of current therebetween and movable in another direction to effect the disconnection thereof from the said switch element to thereby interrupt the said path for the flow of cur rent between the said electrodes, plurality of tubes extending between the said electrodes, electrically conductive vaporizable fluids of different heat conductivity contained within said tubes operative upon move ment of said electrodes in the one direction to form parallel paths for the flow of current between said electrodes and in shunt connection with thesaid path by way of said switch element, the said fluids being immiscible and being vaporized responsive to flow of current therethrough upon movement of said electrodes in the said another direction from connection with e said switch element, the vaporization of the fluids .Jeing operative to eject the same from the said tubes to interrupt the flow of cur ent tlerethrough be tween the said electrodes, and chambers carried by said electrodes operative to receive the said fluids ,ject from the tubes upon said vaporiza thereof.

6, in an intern or electric circuits, a electrodes coznpris ing term als for an r c ic c rcuit movable into and out of (30117 cction 'r switch to establish a path for the new of current between said electrodes by way of element, plurality of tubes of material ending between said vaporizable electricallv conduct cflere it specific gravity a trical conductivity con un tubes operative t fo" p2 as for the s d electron-es and said path by said way of the fluids being vapo of current ther throu id electrodes i1 switch element, fluids being operatthe said tubes to inter rent theretht'ough l mt chamber carr ed by one communicating wit 7 ition ha thron i. for the through upon more from and i 'o conne' element, the fluid of h flowin through the s the lower specific ried by the o her of s ld electrodes h ving a connection th one a. sa d tul es to permit the flow of one of said 1" thereinto, and conduit connectin the said chambers operative to accelerate th movement of one of said fluids into the t said chamber from the tube connected with the second said chamber.

I r l said electrodes, a

, a chamber carsrenan HUMP. 

